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Selecting/excluding sets of columns in pandas [duplicate]
...passed as argument removed.
Here, the result is used to remove columns B and D from df:
df2 = df[df.columns.difference(['B', 'D'])]
Note that it's a set-based method, so duplicate column names will cause issues, and the column order may be changed.
Advantage over drop: you don't create a cop...
Drop unused factor levels in a subsetted data frame
...t, so the mydf <- droplevels(mydf) solution suggested by Roman Luštrik and Tommy O'Dell below is preferable.
– Johan
May 9 '14 at 10:41
1
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How to have the cp command create any necessary folders for copying a file to a destination [duplica
...
To expand upon Christian's answer, the only reliable way to do this would be to combine mkdir and cp:
mkdir -p /foo/bar && cp myfile "$_"
As an aside, when you only need to create a single directory in an existing hierar...
Favourite performance tuning tricks [closed]
...
Here is the handy-dandy list of things I always give to someone asking me about optimisation.
We mainly use Sybase, but most of the advice will apply across the board.
SQL Server, for example, comes with a host of performance monitorin...
How to override !important?
...ing the !important modifier
Simply add another CSS rule with !important, and give the selector a higher specificity (adding an additional tag, id or class to the selector)
add a CSS rule with the same selector at a later point than the existing one (in a tie, the last one defined wins).
Some exa...
How can I delay a method call for 1 second?
...und this solution to be easier than performSelector when mixing straight C and ObjC
– Paul Slocum
Jul 17 '13 at 23:25
1
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Creating .pem file for APNS?
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Here is what I did, From:blog.boxedice.com and "iPhone Advanced Projects" chapter 10 byJoe Pezzillo.
With the aps_developer_identity.cer in the keychain:
Launch Keychain Access from your local Mac and from the login keychain, filter by the Certificates category. Yo...
String is immutable. What exactly is the meaning? [duplicate]
...ith the fuss of immutability, let's just take a look into the String class and its functionality a little before coming to any conclusion.
This is how String works:
String str = "knowledge";
This, as usual, creates a string containing "knowledge" and assigns it a reference str. Simple enough? Le...
Is there a difference between “throw” and “throw ex”?
... ex resets the stack trace (so your errors would appear to originate from HandleException)
throw doesn't - the original offender would be preserved.
static void Main(string[] args)
{
try
{
Method2();
}
catch (Exception ex)
{
Console.Write(ex.StackTrace.ToString()...
How to test an Android Library Project
I am writing an Android Library Project basing on Android Bitmap class (call it AndroindLib) which contains only utility class (no activity). I tried to test it using Android JUnit, but it keeps complaining that can't find the AnroidLib.apk
...